Symptoms of low platelet count, or thrombocytopenia, include blood in urine or stools, excessive bruising, prolonged bleeding from cuts and petechiae, which is a rash of small, reddish-purple spots, according to Mayo Clinic. Platelets perform a vital role by clumping in the blood vessels to stop blood loss.
Low platelet count can be determined by a simple blood test. If the test shows that a patient has less than 150,000 platelets per microliter, a diagnosis of thrombocytopenia can be made, according to Mayo Clinic.
If platelet levels are dangerously low, a patient can be treated with medication or blood transfusions. In addition, sports with a high risk of injury should normally be avoided.